Abstract
Advances in microelectromechanical systems (MEMS) have enabled the widespread development of sensors for a variety of consumer, automotive, and wearable healthcare electronics applications. However, there is increasing interest in the development of highly accurate MEMS inertial sensors for a variety of emerging applications, for e.g., navigation systems for pedestrians and autonomous vehicles, and seismic and gravity imaging, where the traditional attributes of MEMS (miniaturization and system integration) are combined with scalable transduction principles to enable highly accurate physical measurements. Resonant approaches to measurement of forces and displacements in MEMS devices have enabled significant advances in accuracy of MEMS inertial sensors in recent years, assisted by parallel advances in wafer-level encapsulation techniques, interface circuits, and approaches to mitigate temperature sensitivity, also applied to products in MEMS timing and frequency control.
This talk will describe the evolution of vibrating beam MEMS accelerometers demonstrating exceptional long-term stability for applications in gravimetry and seismology. Device sensitivity and stability is demonstrated through the tracking of Earth tides and recording of ground motion corresponding to a number of teleseismic events. MEMS-based gravity instruments are now being developed for applications such as geotechnical surveying, planetary exploration, and CO2 storage monitoring. These results demonstrate the potential of vibrating beam MEMS accelerometers for high-resolution and stable measurements with wider implications for precision measurement employing other resonant-output MEMS devices such as gyroscopes and magnetometers.
Bio
Ashwin A. Seshia is a Professor of Microsystems Technology in the Department of Engineering at Cambridge University and a Fellow of Queens’ College, Cambridge. He received his B.Tech. degree in Engineering Physics from IIT Bombay in 1996, and the MS and PhD degrees in Electrical Engineering and Computer Science from the University of California, Berkeley in 1999 and 2002 respectively.
His research interests include microelectromechanical systems (MEMS) design, particularly in relation to sensors and sensor systems. Ashwin is a co-founder of two companies, 8power and Silicon Microgravity, that were formed to translate research in energy harvesting enabled sensor systems for condition and structural health monitoring, and MEMS-based gravity and inertial sensing, respectively. Ashwin received the 2018 IEEE Sensors Technical Achievement Award (Advanced Career - Sensor Systems) "for pioneering contributions to resonant microsystems with application to sub-surface density contrast imaging and energy harvesting systems". He is a distinguished lecturer of the IEEE Sensors Council (2020-2022). Ashwin is currently an Editor of the IEEE Journal of Microelectromechanical Systems and a member of the executive committee of the European Frequency and Time Forum. He has previously served on the editorial boards of the Journal of Micromechanics and Microengineering (2015-2016), the IEEE Transactions on Nanotechnology (2015-2017), and the IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control (2011-2021).
Ashwin is a Fellow of the Institute of Physics (IOP), a Fellow of the Institution for Engineering and Technology (IET) and a Fellow of the Institute of Electrical and Electronics Engineers (IEEE).